Central switch for pneumatic dispatch systems



March 8, 1955 PRlETZEL 2,703,687

CENTRAL SWITCH FOR PNEUMATIC DISPATCH SYSTEMS Filed May 17, 1952 4 Sheets-Sheet 1 lfliinuq L llllllllVll k Y Z lllllllRllllM A? mu em 1 INVENTOR NO/PBEET FE/EI'ZZ ATTORNEY N. PRIETZEL March 8, 1955 CENTRAL SWITCH FOR PNEUMATIC DISPATCH SYSTEMS Filed May 17, 1952 4 Sheets-Sheet 2 FIG. 2.

INVENTOR A/O/PBE/PT PF/E 7262 BY ATTORNEY March 8, 1955 N. PRIETZEL 2,703,687

CENTRAL SWITCH FOR PNEUMATIC DISPATCH SYSTEMS Filed May 17, 1952 4 Sheets-Sheet s l #60 l i l I 4| I l I A25 1 i J 1 11* w v INVENTOE NOEfiEET P/P/ETZEZ N. PRIETZEL March 8, 1955 CENTRAL SWITCH FOR PNEUMATIC DISPATCH SYSTEMS 4 Sheets-Sheet 4 Filed May 17, 1952 FIG. 6.

FIG. 7.

INVENTOR NORBEET PIE/ETZEL ATTORNEY ml i w //IIII!III fl I IMHIK nu w o ill}! 7 7 Ir 1 v w j l. |Fr l 2- w. M l' o 2, Z

United States Patent CENTRAL SWITCH FOR PNEUMATIC DISPATCH SYSTEMS Norbert Prietzel, Berlin, Germany, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application May 17, 1952, Serial No. 288,497

Claims priority, application Germany May 17, 1951 6 Claims. (Cl. 243-29) It is known in pneumatic dispatch systems to provide so-called central switches at points where two or more tube routes branch off or intersect. Such switches might be operated manually, e. g. by remote control from the point of dispatch, or automatically in response to directive markings in the form of characteristically positioned contact members which are presented by the oncoming carrier to suitable detecting means at the junction point. Thus, there is generally provided a bus tube into which a plurality of incoming tubes may merge and from which the outgoing tubes extend, the carrier being selectively directed into one of these outgoing tubes by means of switch blades or deflectors set electrically under the control of the detecting means.

In known arrangements of this description it has been found that the carriers, provided in the usual manner with felt caps designed to engage the guiding surfaces of the tube, will break into an uncontrollable tumbling movement (manifesting itself in strong impact noises) at these junction points, thereby causing not only the felt caps but also the contact-carrying portions of the carriers to impinge upon the guiding surfaces and/or upon the switch blades.

An object of the present invention is to provide means for positively guiding the carriers at the junction points in such manner that any tumbling and tossing thereof will be substantially avoided, wit a view to increasing the efficiency of the system, reducing wear in general and protecting in particular the sensitive contact members of the carriers.

A related object of the invention is to provide, at locations where movement of the carrier is due to inertia (and/or gravity) rather than to a pressure differential, guide means replacing the tubes and making only relatively limited contact with the carrier, thereby reducing friction and diminishing the risk of contact, especially in curves, between the guiding surfaces and sensitive parts of the carrier.

According to the present invention there is provided, at a junction between an incoming and an outgoing tube, a guide channel for a carrier comprising a plurality of substantially parallel, preferably round rods or rails adapted to engage the carrier at spaced-apart points. According to a more specific feature of the invention the guide channel comprises four substantially equidistant rods divided into two pairs, one pair extending from the incoming to the outgoing tube, the other pair being interrupted at a switching point and replaced by a defiector or baffle which cooperates with the rods of the first pair to form a three-point guide for the carrier. The incoming section of the interrupted pair of rods may, according to a further feature of the invention, terminate in rigid but yieldably mounted strips of cushioning material (e. g. felt) preferably reinforced by steel strips.

The above and other objects and features of the invention will become apparent from the following detailed description, reference being had to the accompanying drawing in which:

Fig. 1 is a somewhat diagrammatic view of a central switch according to the invention, with two incoming and two outgoing tubes as well as a so-called error tube positioned between the latter;

Fig. 2 is a perspective view, on a larger scale, of the 2,703,687 Patented Mar. 8, 1955 lower portion of the switchof Fig. 1 including the outgoing tubes;

Fig. 3 shows, in cross section, two pairs of guide rods laccording to the invention and a carrier engaged there- Fig. 4 is an enlarged view of a steel-reinforced felt strip shown in Fig. 1;

Fig. 5 is a view of the outer frame of the switch of 'gigc.1 1, showing the solenoids used for throwing the switch la es;

Fig. 6 is a view similar to Fig. 1, showing a modified central switch, according to the invention, with four incoming and four outgoing tubes; and

Fig. 7 is a detail view on the line 77 of Fig. 6.

Referring first to Figs. 1 to 5, there is shown a central switch forming a junction between two incoming tubes 101, 102 on the one hand and two outgoing tubes 108, 109 on the other. The switch comprises an outer frame 10 supporting feeler means, shown schematically at 42, which sense the directive markings on an incoming carrier and, in a manner known per se, selectively operate baflles 30, 31 with the aid of solenoids such as indicated at 24 (Fig. 5). These bafiles, when selectively thrown into their operative position (shown in Fig. 2 for the baffle or switch blade 31), deflect the oncoming carrier into one of the two outgoing tubes 108, 109; should both baffles 30, 31 be in their normal position, owing to failure of the detector means 42 properly to sense the markings on the carrier, then the latter will be directed into the error tube 105.

The carriers arriving over either of the two incoming tubes 101, 102 all pass through a central guiding section 34 which is constituted by two pairs of round rods designated 1 and 2, respectively, in Fig. l. The rods 1a, 1b, forming the pair 1, and 2a, 2b, forming the pair 2, engage the carrier 50 at equidistant, circumferentially spaced points as best shown in Fig. 3. The pair 1 extends from the incoming tube 101 to the outgoing tube 109 and is common to an incoming guiding section 17 and to an outgoing guiding section 9; the pair 2 similarly extends from the incoming tube 102 to the outgoing tube 108 and is common to an incoming guiding section 18 and to an outgoing guiding section 8. Each guiding section 17, 18, 8, 9 is-similar to the central section 34 and consists of an outer pair of rods, represented by the common pair 1 or 2, respectively, and of a foreshortened inner pair indicated at 13, 14 in the case of the incoming sections 17, 18, respectively, and at 5, 6 in the case of the outgoing sections 9 and 8, respectively. Two pairs of short guide rods 39, 40 are also provided at the entrance of error tube 105 for positively directing the carrier into said tube.

The individual rods 5a, 5b, 6a, 6b, 39a, 39b and 40a, 40b of the short pairs 5, 6, 39 and 40 are shown in Fig. 2. This figure also shows how the various rods are curved with a sufficiently large radius to avoid contact between these rods and any part of the body of carrier 50 other than its felt caps 51, 52. The rods are mounted on the frame 10 by means of brackets 41 schematically indicated in Fig. l by dots.

The foreshortened inner rods 13, 14 of the incoming guiding sections 17, 18 terminate in rigid guide strips 11, 12 of cushioning material, such as felt, which, as shown in Fig. 4, are reinforced by steel strips 16, 16". These guide strips are pivotally mounted, as at 15, in a lockout arrangement which, as illustrated in dotted lines in Fig. 1, causes one pair of strips, say the strips 11, to be deflected by an incoming carrier from tube 102 into an extreme position substantially parallel to the associated outer rods 2, the deflected strips 11 urging the other pair of strips 12 into contact with the outer rods 1 so as to block off the other incoming channel section 101 until the carrier from tube 102 has passed. The guide strip 12 operates against strip 11 in similar fashion upon the arrival of a carrier from tube 101.

It will thus be seen that a carrier arriving, say, through tube 102 is first received by the four rods 2, 14 of guiding section 18, is then directed by another four-point guide comprising the elements 11, 2 toward the central section 34 consisting of four rods 1a, 1b, 2a, and 2b, and

thereafter (assuming the bafile 31 to have operated) continues by way of a three-point guide comprising the elements 31, 2 toward channel section 8, the latter being similar to section 18 and consisting of the four rods 6a, 6b, 2a and 2b, and finally enters the outgoing tube 108. On passing through the latter tube the carrier operates contacts, designated 25 in Fig. 5, serving to restore the deflector or baflie 31 to its normal position. Thus in Fig. 5 the solenoid 24, which operates said battle, is shown provided with a movable core 240 connected to a link 26 which in turn is pivotally connected with a bell crank lever 28, the latter being pivoted at 27 and tension-ed from a spring 29 to withdraw the core from the solenoid winding when the latter becomes de-energized. A holding circuit 60 for the solenoid, schematically indicated in Fig. 5 and including contacts 25 in series with contacts 61 which are mechanically closed by its core when the solenoid'24 is energized, is thereby broken and the bafiie returns to the position shown in Fig. 1.

In Fig. 6 the central switch 200 comprises four inlet guiding sections 19, 20, 21 and 22, connected to incoming tubes 201, 203, 204 and 202, respectively, a central section 35, and four outlet guiding sections 46, 47, 43, 49 connected, respectively, to outgoing tubes 206, 207, 208 and 209. Three pairs of guide strips 36, 37 and 38 take the place of the strips 11, 12 of Fig. 1 and operate in analogous manner to form a four-point guide for an incoming carrier while temporarily blocking ofl all other incoming channel sections. The deflectors 30, 31 of Fig. 1 are replaced by four bafiles 23, 32, 33 and 43 forming two pairs of deflector members complementing each other in the manner best seen in Fig. 7; thus the forwardly positioned member of a pair, e. g. the bafile 32, is provided with a slot adapted to receive the tip of the rear member, e. g. the baifle 23, so that together they will form a continuous guiding strip when both are deflected in the manner shown in dotted lines in Fig. 6. It will, of course, be understood that the apparent distance between the two pairs of rods of section 49, as seen in Fig. 6, will be less than that between the outer pair of rods and operated baffle 23 or 32, because of the change from three-point guidance to four-point guidance.

It will be seen that in the arrangement of Fig. 6 either one or the other of the primary baflies 32, 33 must be operated but that the corresponding secondary baflle 23 or 43 may be in its normal or in its deflected position, depending upon the selection to be made between the associated outgoing tubes 207, 209 and 206, 208. Should both primary baflies be normal, then the carrier will be directed into the error tube 205.

Although the invention has been described with reference to certain specific embodiments, it should be understood that the same is capable of many modifications and adaptations without for this reason departing from the spirit and scone of the appended claims.

What is claimed is:

1. A pneumatic dispatch tube switch adapted to interconnect a plurality of incoming and outgoing tubes comprising a housing having one end coupled to said incoming tubes and its opposite end coupled to said outgoing tubes, a central rail portion within said housing common to all of said tubes, a plurality of movable switch blades, each associated with a pair of adjacent outgoing tubes, each blade pivotally mounted to shunt a pneumatic carrier from said central rail portion to a selected one of the tubes of said pair, separate rail means within said housing associated with said incoming tubes to guide carriers from said incoming tubes to said central rail portion, said separate rail means comprising a plurality of movable guide strips having an open and a closed position, each associated with at least one of said incoming tubes and adapted to be actuated to its open position by the impingement thereagainst of a carrier arriving from its associated tube, said strips mounted in mutual abutting relation, whereby an opened guide strip causes closure of an opened adjacent guide strip thereby to prevent but one carrier from entering said central rail portion at a time.

2. A pneumatic dispatch tube switch as claimed in claim 1, wherein said central rail portion comprises two parallel pairs of round rods equidistantly spaced to form a substantially square guiding track.

3. A pneumatic dispatch tube as claimed in claim 2, wherein said pairs of rods comprise a first pair extending rom an outgoing tube to said central rail portion, said other pair of rods extending from said outgoing tube to said switch blade, a surface of said blade adapted to cooperate with said first pair of rods to provide a threel-lpoint support for a carrier passing through said switc 4. A pneumatic dispatch tube switch as claimed in claim 3, further comprising additional switch blades in staggered relation with said first named switch blades, said additional blades adapted to form an extended thirdpoint support for a carrier passing through said switch.

5. A pneumatic dispatch tube switch as claimed in claim 1, wherein said separate rail means comprises a pair of outer guide rods extending between said incoming tubes and said central rail portion.

6. A pneumatic dispatch tube switch as claimed in claim 1, wherein at least one of said guide strips is positioned between a pair of adjacent incoming tubes and is adapted to be impinged against by a carrier arriving from 0 either of said adjacent tubes.

References Cited in the file of this patent UNITED STATES PATENTS Germany Feb. 21, 1937 

